Apparatus for winding tapped coils



Nov. 28, 1961 R. D. FORSBERG 3,010,667

APPARATUS FOR WINDING TAPPED COILS Filed March 24, 1958 INVENTOR. ROBERTD. FORSBERG United States Patent@ 3,010,667 APPARATUS FOR WINDING TAPPEDCOILS Robert D. Forsberg, Cambridge, Mass., assignor to Computer ControlCompany, Inc., Wellesley, Mass, a corporation of Massachusetts FiledMar. 24, 1958, Ser. No. 723,248 7 Claims. (Cl. 242-9) The presentinvention relates in general to coil winding apparatus and moreparticularly concerns novel methods and means for continuously windingcoils with selectively displaced taps. In accordance with the inventiveconcepts, tapped coils are rapidly wound with the taps accuratelypositioned while minimizing the danger of wire breakage.

Tapped coils are especially useful in a lumped-parameter delay line.Such a delay line advantageously uses a multi-tap coil helically woundon a small diameter cylindrical dielectric coil form. The taps furnishconvenient points for connecting small shunt capacitors, and the spacingbetween taps, which need not be uniform, is determined by a number ofengineering design factors, including the desired delay interval.However, once the spacing is specified, it is frequently required thatit be Other features, objects and advantages of the invention willbecome apparent from the following specification when read in connectionwith the accompanying drawing in which:

FIG. 1 shows a tapped coil wound according to the invention; a

FIG. 2 shows an embodiment of the novel coil winding machine; and

FIG. 3 illustrates an alternative way of storing an auxiliary wiresupply.

With reference now to the drawing and more particularly FIG. 1 thereof,there is illustrated a tapped coil wound according to the invention. Thecoil 11 is preferably wound on dielectric coil form 12 with a number oftaps 13 which may be spaced uniformly or non-uniformly as desired.

With reference to FIG. 2, there is shown an embodiment of the novel coilwinding machine, which essentially comprises a conventional lathespecially adapted to perform the functions to be described.

Thus, the machine includes a base 14 supporting headstock 15 andtailstock 16. Chuck 17 and socket 18 are rotatably supported in therespective ends of the machine, and in turn rotatably support coil form12. With lock Patented Nov. 28, 1961 maintained quite closely in orderto achieve operation screws 21 and 22 tight, chuck 17, coil form 12 andsocket within the desired tolerances. 18 rotate in unison.

A major problem in winding such coils is the provision Chuck 17 carriesan arm 23 extending radially outward of taps. This is typicallyaccomplished by stopping a from the coil form axis. A short rod 24extends perpenconventional coil winding machine at each prescribeddicularly from arm 23 toward the right. Spool 25 carries point, twistingthe wire and proceeding to the next tap. an auxiliary supply of wire 26held under tension by an These coils are, therefore, relativelyexpensive, non-unienclosed spring (not shown), preferably a constantforce form, and most significantly, mechanically unreliable as spring,such as a Neg-ator. Spool 25 is supported on the taps frequently breakofi during condenser assembly. short rod 24 and normally rests flushagainst arm 23, as

The present invention contemplates and has as a priillustrated. However,at selected intervals, in order to mary object the provision of novelmethods and means provide the desired taps, it is moved to the right sothat for automatically winding and inserting taps on a coil of itoccupies the position indicated by the broken lines 27. this type toachieve accurately spaced taps of greater A long highly-polished rod 31extends from tailstock mechanical strength at higher speed and reducedcost. 16 parallel to the coil form axis almost to the left end Anotherobject of the invention is to employ techniques of coil form 12. As isclear from the drawing, short rod for winding tapped coils in accordancewith the preced- 4O 24 is further from the coil form axis than long rod31. ing object readily adaptable for automatic production With spool 25in its normal position, wire strand 32 clears of coils withaccurately-spaced, mechanically-strong taps. the left end 33 of rod 31.When spool 25 is is in posi- According to the invention, a prescribedlength of wire tion 27, wire strand 32 occupies the position 34 and froma main wire supply is first wound around an auxoverlaps the end of rod31. iliary spool. One end of the coil form is supported within Theentire assembly consisting of chuck 17, arm 23, rod a chuck having anarm extending radially outward from 24, auxiliary spool 25, coil form 12and socket 18 is the axis of the coil form. The auxiliary spool issuprotated when the driving motor (not shown) is energized. ported on ashort rod at the end of the arm extending A Wire supply tension andtransport mechanism 45 parallel to the coil axis toward the other end ofthe threadably engages a lead screw 44 and is guided along coil. A fixedlong rod extends parallel to the coil axis a lower rod 43. The main wiresupply is carried on from the latter end for less than the length of thecoil spool 46 which unwinds about lower rod 43 as the coil form. Theauxiliary spool is free to slide along the short is wound. A strand ofwire 47 is fed from spool 46 rod but normally rests snugly against thearm. to coil form 12 over pulleys 51. Lead screw 44 is rotated At thestart of a winding operation, a taut strand of in synchronism with therotation of coil form 12 by the wire between the/auxiliary spool and themain wire supply motor drive. rests against the coil form at the endsupported in the The machine operates as follows: As chuck 17 rotateschuck. The chuck, arm and auxiliary spool are rotated in the directionindicated by arrow 55, wire pays out about the coil axis, causing wireto unwind from the from the main Wire supply, spool 46. This wire ishelicalmain wire supply and around the coil form. As the coil ly wrappedabout the rotating coil form 12 as the supply is wound, the main wiresupply travels in a direction moves to the right in synchronism. Withstrand 32 in generally parallel to the coil form axis and away from theindicated position, rod 31 has no efiect on the windthe chuck. The longrod remains stationary. ing process.

At a point where a tap is desired, the wire strand from When it isdesired to insert a tap, strand 32 is displaced the auxiliary spool tothe coil form is moved away from to the right, by hand, or preferably,by moving auxiliary the arm so that it is caught by and wrapped aroundthe spool 25 to the position indicated by lines 27. Strand long rod asthe winding assembly rotates. At the end of 32 is now positioned asindicated by the dotted lines 34 a revolution, the strand is againwithdrawn to its normal and overlaps rod 31. As chuck 17 continues torotate, position and the normal winding process continues. The a loop,like loop 56, '57 or 58, is formed about the staloop formed by the wirestrand overlapping the long tionary rod 31. Wire for this loop is payedout from auxrod travels in a direction parallel to the axis of theiliary spool 25. coil form and away from the chuck as the winding as- Atthe completion of one revolution (or more if a sembly rotates. strongerloop is desired) strand 32 is again displaced to the left so that itclears the left end 33 of rod 31. However, the loop formed on thisrevolution translates to the right as the coil form continues to rotate.It is to be noted'that the specific segment of wire which formed theloop on this revolution is wrapped around the coil form as the looptranslates to the right. This is because a segment of wire in the loop,in addition to theztranslational motion to' the right, moves, .asindicated by the arrows, about the loop center.

' When the 'desirednumber of turns are wound, the

motor is stopped. Before removing the coil, a coat of Q-m'ax or othercoil dope is applied to the side away from the loops forming the taps toprevent loosening of the windings; The loops may then be cut at theircenter without removing rod 31, cleaned of insulation, and soldered. Itis unnecessary to ,twist the taps tightly as in conventionally-Woundlines, thus eliminating a major cause of breakage. For manyapplications, such as in etched circuits, they need not be twisted'atall. Coil form '12 is then removed to provide the finished coil 11 ofFIG. 1. 7

With reference to'FIG. 3, there is illustrated an alternativearrangement for storing the auxiliary wire supply. A spool 61 carriesthe auxiliary supply of wire 26 on hub 62 of chuck 17. Wire from spool61 is passed over pulley 63 supported on rod 24 in the same manner asspool 25 of FIG. 2. Strand 32 normally occupies a position to the leftof the left end 33 of rod 31 when pulley 63 is flush against arm 23.When pulley 63 is moved to the position 64, strand 32 is again moved toposition 34 overlapping long rod 31 to produce the same result describedabove. Ibis important to note that any means which will cause strand 32to overlap rod 31 during one revolution, such as moving rod 31 to theleft'or manually moving strand 32 to the right, will provide the desiredloops.

In an alternate winding procedure, the entire coil may be Wound withouttaps and the wire from spool 46 cut and fastened at the right end, forexample, to screw 22. The taps may then be introduced as above, spacedthe desired number of turns apart, and allowed to translate to the rightuntil they are within the'desired number of turns fromthe right-hand endof the coil. t

It is apparent that the tap-introducing mechanism may be controlled bypreset counters, thus making the wind ing process completely automatic.Moreover, the pitch of the coilmay be varied by choosing appropriatelead screwsor ratios of pulley 54 diameter to pulley 52 diameter.Numerous other modifications of and departures from the specifictechniques disclosed herein may be practiced by those skilled in the artwithout departing from the inventive concepts. Consequently, theinvention isto be construed as limited only by the spirit and scope ofthe appended claims.

What is claimed is: v

1. Apparatus for winding a tapped coil upon a coil form comprising,means for supporting a principal source of. continuouswire, means forsupporting anauxiliary source containing a portion of said continuouswire, means forunwinding wire. from said principal source upon said coilformyand means cooperating with said auxiliary source for forming wireloops constituting taps for said coil.

2. Apparatus in accordance with claim 1 wherein said last mentionedmeans supports said loops for movement along said coil form during theunwinding of wire from said principal source upon said coil form.

3. In coil winding apparatus having means for winding wire over thesurface of a coil form, a supporting base, first and second meansrotatably supported by said base for holding said coil form at first andsecond opposite ends, respectively, a relatively long red disposedgenerally parallel to'and at a fixed angle about the axis of symmetryof: said coil form, said long rod extending from said first end almostto said second end, a rigid member afiixed to and extending radiallyoutward from said secand means, and a short rod extendingperpendicularly fromi said rigid member toward said first end, thedistance between said axis of symmetry and said short rod exceeding thatbetween said axis and said long rod.

4. In a coil Winding machine having means for winding wire over thesurface of a coil form, a supporting base, first and second meansrotatably supported by said base and adapted to secure a generallycylindrical coil form at first and second opposite ends, respectively, along rod afilxed to said base adjacent said first end and extendinggenerally parallel to-the axis of said coil form almost to said secondend, said'second means having a member extending radially outward fromsaid axis, a short rod extending perpendicularly from said member towardsaid first end at a distance from said axis greater than the distancebetween said long rod and said axis.

5. Coil winding apparatus in accordance with claim 4 and furthercomprising a spool slidable along and rotatable about said short rod. I

6. Coil winding apparatus in accordance with claim 5 and furthercomprising, a support rod secured to said base, a rotatable threaded rodsupported by said base parallel to said support rod and axis, a wiresource tension and transport mechanism slidable along said support rodand threadably engaging said threaded rod, and means for synchronouslyimparting rotative motion to said threaded'ro-d and said second means.

7. A method of winding a tapped coil upon a coil form having an axisparallel to a smooth rod with a filament having a taut portion at oneend of said rod, including the steps of rotating said coil form and saidtaut portion about the coil form axis while feeding another portion ofsaid continuous filament disposed away from said taut portion about andover the surface of said coil form, and relatively displacing said tautportion and said smooth rod whereby the former overlaps the latter.

References Cited in the file of this patent UNITED STATES PATENTS2,401,676 Weber June 4, 1946 2,406,846 Muller Sept. 3, 1946 -2,655,717Dunn Oct. 20, 1953 Duenke Nov. 27, 1956

